Pharmaceutical compositions and methods of inhibiting gastric acid secretion

ABSTRACT

Pharmaceutical compositions and methods of inhibiting gastric acid secretion by administering N-aminomethyl heterocyclic thioacetamide compounds.

This application is a continuation-in-part of Ser. No. 266,181, filed June 26, 1972, now U.S. Pat. No. 3,873,536 which is a continuation-in-part of Ser. No. 220,418, filed Jan. 24, 1972 now abandoned.

This invention relates to new N-aminomethyl heterocyclic thioacetamide compounds having pharmacodynamic activity. In particular, these compounds inhibit gastric acid secretion.

The compounds of this invention are represented by the following formula:

FORMULA I ##EQU1## in which: R₁ is 2-pyridyl, 2-pyrimidyl, 4-pyrimidyl, 2-pyrazinyl, 2-pyrrolyl, 2-quinolyl, 2-thiazolyl or 4-thiazolyl;

R₂ is hydrogen, lower alkyl, lower alkenyl or -(CH₂)_(n) -phenyl;

R₃ is di-lower alkylamino, N-lower alkyl-N-phenylamino, pyrrolidino, piperidino, morpholino or N-lower alkylpiperazino and

n is 0 or 1.

This invention also includes pharmaceutically acceptable acid addition salts of the compounds of Formula I.

The pharmacologically active compounds of this invention have the basic structure of Formula I. However, it is apparent to one skilled in the art that well known nuclear substituents such as lower alkyl, lower alkoxy or halogen may be incorporated on the heterocyclic rings of R₁ and the phenyl rings. These substituted compounds are used as are the parent compounds.

Preferred compounds of this invention are represented by Formula I above in which R₂ is hydrogen or lower alkyl and R₃ is di-lower alkylamino, pyrrolidino, piperidino or morpholino.

Advantageous compounds of this invention are represented by Formula I in which R₁ is 2-pyridyl, R₂ is lower alkyl and R₃ is diethylamino, pyrrolidino or morpholino.

Most preferably, in the compounds of Formula I, R₁ is 2-pyridyl.

Particularly advantageous compounds of this invention are represented by Formula I in which R₁ is 2-pyridyl, R₂ is methyl, ethyl or isopropyl and R₃ is diethylamino, pyrrolidino or morpholino. Included in this group are 3-methyl-N-morpholinomethyl-2-(2-pyridyl)thiobutanamide, N-morpholinomethyl-2-(2-pyridyl)thiopropanamide, 3-methyl-N-pyrrolidinomethyl-2-(2-pyridyl)thiobutanamide and N-diethylaminomethyl-3-methyl-2-(2-pyridyl)thiobutanamide.

The compounds of this invention produce inhibition of gastric acid secretion. This activity is demonstrated by administration to pylorus ligated rats at doses of about 10 to about 50 mg./kg. orally. Also, this activity is demonstrated by administration to chronic gastric fistula rats (Brodie et al., Amer. J. Physiol. 202:812-814, 1962) at doses of about 50 mg./kg. orally. In these procedures, compounds which produce an increase in gastric pH or a decrease in the volume of gastric juice or both are considered active.

These compounds show antiulcer activity in the restraint-stress method in which on oral administration to rats these compounds inhibit the development of experimental ulcers.

The compounds of this invention are prepared as follows: ##EQU2## The terms R₁ -R₃ are as defined above.

According to the above procedure, a heterocyclic thioacetamide is reacted with formaldehyde and an amine. The reaction is preferably carried out in an organic solvent, such as a lower alkanol, for example methanol. The reaction is carried out, for example, at about -40°C. to about 90°C., preferably at the lower temperatures when R₂ is hydrogen.

The heterocyclic thioacetamide starting materials are known to the art or are prepared, for example, by reacting the corresponding substituted acetonitrile (R₁ R₂ CH--CN) with hydrogen sulfide in the presence of base such as an amine or by reacting with ammonium polysulfide. The substituted acetonitriles may be prepared from substituted ketones or carboxaldehydes (R₁ R₂ C=O) by reducing to the corresponding alcohol using a reducing agent such as sodium borohydride, then treating the alcohol with a chlorinating agent such as thionyl chloride and treating the resulting chloride with an alkali metal cyanide such as sodium or potassium cyanide.

The pharmaceutically acceptable acid addition salts of the compounds of Formula I are formed with organic and inorganic acids by methods known to the art. For example, the base is reacted with an organic or inorganic acid in aqueous miscible solvent, such as acetone or ethanol, with isolation of the salt by concentration and cooling or in aqueous immiscible solvent, such as ethyl ether or chloroform, with the desired salt separating directly. Exemplary of the salts which are included in this invention are maleate, fumarate, succinate, oxalate, benzoate, methanesulfonate, ethanedisulfonate, benzenesulfonate, acetate, propionate, tartrate, citrate, hydrochloride, hydrobromide, sulfate, sulfamate, phosphate and nitrate salts.

The compounds of this invention are administered internally either parenterally, rectally or, preferably, orally in an amount to produce the desired biological activity.

Preferably, the compounds are administered in conventional dosage forms prepared by combining an appropriate dose of the compound with standard pharmaceutical carriers.

Pharmaceutical compositions having gastric acid secretion inhibitory activity, in dosage unit form, comrising a pharmaceutical carrier and a gastric acid secretion inhibiting amount of a compound of Formula I or a pharmaceutically acceptable acid addition salt thereof are objects of this invention.

The pharmaceutical carrier may be for example a solid or a liquid. Exemplary of solid carriers are lactose, magnesium stearate, terra alba, sucrose, talc, stearic acid, gelatin, agar, pectin, acacia or cocoa butter. The amount of solid carrier will vary widely but preferably will be from about 25 mg. to about 1 gm. Exemplary of liquid carriers are syrup, peanut oil, olive oil, sesame oil, propylene glycol, polyethylene glycol (mol. wt. 200-400) and water. The carrier or diluent may include a time delay material well known to the art such as, for example, glyceryl monostearate or glyceryl distearate alone or with a wax.

A wide variety of pharmaceutical forms can be employed, for example the preparation may take the form of tablets, capsules, powders, suppositories, troches, lozenges, syrups, emulsions, sterile injectable liquids or liquid suspensions or solutions.

The pharmaceutical compositions are prepared by conventional techniques involving procedures such as mixing, granulating and compressing or dissolving the ingredients as appropriate to the desired preparation.

The methods of inhibiting gastric acid secretion in accordance with this invention comprise administering internally to an animal an effective amount of a compound of Formula I or a pharmaceutically acceptable acid addition salt thereof. The active ingredients will preferably be administered in dosage unit form as described above.

The compounds of this invention will be administered in a daily dosage regimen of from about 10 mg. to about 2 g., preferably from about 25 mg. to about 1 g. Advantageously, equal doses will be administered one to four times per day. Dosage units will contain from about 10 mg. to about 500 mg., preferably from about 25 mg. to about 250 mg., of the active ingredient.

When administration is carried out as described above, gastric acid secretion is inhibited.

One skilled in the art will recognize that in determining the amounts of the active ingredients in the claimed compositions and used in the claimed methods, the activity of the chemical ingredient as well as the size of the host animal must be considered.

The terms "lower alkyl" and "lower alkoxy" where used herein denote groups having 1-6, preferably 1-4, carbon atoms; "lower alkenyl" denotes groups having 2-6, preferably 2-4, carbon atoms and "halogen" denotes chloro, bromo or fluoro.

The following examples are not limiting but are illustrative of the compounds of this invention and processes for their preparation.

EXAMPLE 1

To a solution of 1.0 g. of 3-methyl-2-(2-pyridyl)-thiobutanamide in 20 ml. of methanol is added, at one time, 0.45 g. of morpholine and 0.42 ml. of a 37% formalin solution. The reaction is stirred for 15 hours at 25°C., then refluxed on a steam bath for 20 minutes. The solvents are evaporated in vacuo and the residue is distilled to give 3-methyl-N-morpholinomethyl-2-(2-pyridyl)thiobutanamide, b.p. 110°-112°C. (0.005 mm.).

EXAMPLE 2

2-Phenyl-2-(2-pyridyl)thioacetamide (1.14 g.) is suspended in 20 ml. of methanol. To the suspension is added 0.49 ml. of morpholine and 0.45 ml. of formalin. The mixture is heated on a steam bath until all of the materials are dissolved. The solution is then cooled and hexane is added. Concentrating to dryness and recrystallizing the residue from isopropanol gives N-morpholinomethyl-2-phenyl-2-(2-pyridyl)thioacetamide, m.p. 128°-130°C.

EXAMPLE 3

By the procedure of Example 1, using the following thioamides in place of 3-methyl-2-(2-pyridyl)-thiobutanamide:

2-(2-pyridyl)thiobutanamide

2-(2-pyridyl)thiopentanamide

2-(2-pyridyl)thiohexanamide

2-(2-pyridyl)thiooctanamide

the products are, respectively:

N-morpholinomethyl-2-(2-pyridyl)thiobutanamide

N-morpholinomethyl-2-(2-pyridyl)thiopentanamide

N-morpholinomethyl-2-(2-pyridyl)thiohexanamide

N-morpholinomethyl-2-(2-pyridyl)thiooctanamide.

EXAMPLE 4

Using 2-(2-pyridyl)-4-thiopentenamide in place of 3-methyl-2-(2-pyridyl)thiobutanamide in the procedure of Example 1, the product is N-morpholinomethyl-2-(2-pyridyl)-4-thiopentenamide.

EXAMPLE 5

To a solution of 2.0 g. (0.013 m.) of 2-(2-pyridyl)-thioacetamide in 30 ml. of methanol at -40°C. is added 1.15 g. (0.013 m.) of morpholine in 6 ml. of methanol and 1.05 ml. of a 37% formalin solution (0.013 m.) in 6 ml. of methanol. The solution is allowed to warm up to -20°C. and kept at this temperature for 48 hours.

The solution is concentrated in vacuo and the residue is deposited on silica gel and chromatographed on a 20 × 1.5 inches dry column, using ethyl acetate as the eluant. The product fraction is evaporated and the residue is distilled in vacuo to give N-morpholinomethyl-2-(2-pyridyl)-thioacetamide.

EXAMPLE 6

By the procedure of Example 5, using the following thioamides in place of 2-(2-pyridyl)thioacetamide:

2-(2-pyrazinyl)thioacetamide

2-(2-quinolyl)thioacetamide

2-(2-pyrrolyl)thioacetamide

2-(6-methyl-2-pyridyl)thioacetamide

2-(5-methyl-2-pyridyl)thioacetamide

2-(4-methyl-2-pyridyl)thioacetamide

2-(3-methyl-2-pyridyl)thioacetamide

2-(5-ethyl-2-pyridyl)thioacetamide

2-(4-methoxy-2-pyridyl)thioacetamide

2-(4-ethoxy-2-pyridyl)thioacetamide

the products are, respectively:

N-morpholinomethyl-2-(2-pyrazinyl)thioacetamide

N-morpholinomethyl-2-(2-quinolyl)thioacetamide

N-morpholinomethyl-2-(2-pyrrolyl)thioacetamide

2-(6-methyl-2-pyridyl)-N-morpholinomethyl-thioacetamide

2-(5-methyl-2-pyridyl)-N-morpholinomethyl-thioacetamide

2-(4-methyl-2-pyridyl)-N-morpholinomethyl-thioacetamide

2-(3-methyl-2-pyridyl)-N-morpholinomethyl-thioacetamide

2-(5-ethyl-2-pyridyl)-N-morpholinomethyl-thioacetamide

2-(4-methoxy-2-pyridyl)-N-morpholinomethyl-thioacetamide

2-(4-ethoxy-2-pyridyl)-N-morpholinomethyl-thioacetamide.

EXAMPLE 7

By the procedure of Example 1, using the following thioamides in place of 3-methyl-2-(2-pyridyl)thiobutanamide:

2-(2-pyrazinyl)thiobutanamide

2-phenyl-2-(2-pyrazinyl)thioacetamide

2-(4-chlorophenyl)-2-(2-pyrimidyl)thioacetamide

2-phenyl-2-(2-thiazolyl)thioacetamide

2-(4,6-dimethyl-2-pyrimidyl)thioacetamide

the products are, respectively:

N-morpholinomethyl-2-(2-pyrazinyl)thiobutanamide

N-morpholinomethyl-2-phenyl-2-(2-pyrazinyl)thioacetamide

2-(4-chlorophenyl)-N-morpholinomethyl-2-(2-pyrimidyl)-thioacetamide

N-morpholinomethyl-2-phenyl-2-(2-thiazolyl)thioacetamide

2-(4,6-dimethyl-2-pyrimidyl)-N-morpholinomethyl-thioacetamide.

EXAMPLE 8

By the procedure of Example 2, using in place of 2-phenyl-2-(2-pyridyl)thioacetamide the following 2-substituted phenyl-2-(2-pyridyl)thioacetamides:

2-(4-chlorophenyl)-2-(2-pyridyl)thioacetamide

2-(2-fluorophenyl)-2-(2-pyridyl)thioacetamide

2-(3-methylphenyl)-2-(2-pyridyl)thioacetamide

2-(4-methoxyphenyl)-2-(2-pyridyl)thioacetamide

the products are, respectively:

2-(4-chlorophenyl)-N-morpholinomethyl-2-(2-pyridyl)thioacetamide

2-(2-fluorophenyl)-N-morpholinomethyl-2-(2-pyridyl)thioacetamide

2-(3-methylphenyl)-N-morpholinomethyl-2-(2-pyridyl)thioacetamide

2-(4-methoxyphenyl)-N-morpholinomethyl-2-(2-pyridyl)-thioacetamide.

EXAMPLE 9

Methyl 4-thiazolyl ketone (12.7 g.) is added to 3.8 g. of sodium borohydride in 100 ml. of isopropanol and the mixture is heated at reflux for four hours. Dilute hydrochloric acid (100 ml.) is added and the mixture is evaporated to dryness. The residue is dissolved in a small volume of water and the aqueous solution is made basic with 5% aqueous sodium bicarbonate solution, then evaporated to dryness. The residue is extracted with ether and the ether is removed from the extract in vacuo to give α-(4-thiazolyl)-ethanol.

A mixture of 8.4 g. of α-(4-thiazolyl)ethanol and 25 ml. of thionyl chloride is heated for four hours on a steam bath, then concentrated in vacuo. The residue is dissolved in water and basified with 5% aqueous sodium carbonate solution. Extracting with ether, then drying and concentrating the extracts gives 4-(α-chloroethyl)thiazole.

A solution of 7.8 g. of 4-(α-chloroethyl)thiazole is added dropwise to a suspension of 5.2 g. of sodium cyanide in 100 ml. of dimethylsulfoxide. The mixture is heated at 50°C. for two hours, then diluted with 150 ml. of a 5% aqueous sodium carbonate solution and extracted with ether. The extract is dried and concentrated to give α-(4-thiazolyl)-propionitrile.

To 12.4 g. of α-(4-thiazolyl)propionitrile in 13 ml. of pyridine is added 5 ml. of triethylamine. Hydrogen sulfide is bubbled into the mixture for two hours. The mixture is heated in a sealed tube at 100°C. for 15 hours, then cooled and concentrated to dryness. The residue is extracted with chloroform and the extract is concentrated to dryness. The residue is recrystallized from chloroform-hexane to give 2-(4-thiazolyl)thiopropanamide.

Using 2-(4-thiazolyl)thiopropanamide in place of 3-methyl-2-(2-pyridyl)thiobutanamide in the procedure of Example 1, the product is N-morpholinomethyl-2-(4-thiazolyl)-thiopropanamide.

EXAMPLE 10

To a solution of 22.2 g. of methyl magnesium chloride in ether is added 10.5 g. of 4-pyrimidinecarbonitrile in tetrahydrofuran. The resulting mixture is heated at reflux for 24 hours, then poured onto ice. To the mixture is added 75 ml. of 25% sulfuric acid. The solution is then made basic with 10% aqueous sodium carbonate solution and extracted with ether. The extracts are dried and concentrated to give methyl 4-pyrimidyl ketone.

By the procedure of Example 9, using methyl 4-pyrimidyl ketone in place of methyl 4-thiazolyl ketone, 2-(4-pyrimidyl)thiopropanamide is obtained.

Using 2-(4-pyrimidyl)thiopropanamide in place of 3-methyl-2-(2-pyridyl)thiobutanamide in the procedure of Example 1, the product is N-morpholinomethyl-2-(4-pyrimidyl)-thiopropanamide.

EXAMPLE 11

By the procedure of Example 10, using 2-(4-chloropyridine)carbonitrile as the starting material, 2-(4-chloro-2-pyridyl)thiopropanamide is obtained.

Using 2-(4-chloro-2-pyridyl)thiopropanamide in place of 3-methyl-2-(2-pyridyl)thiobutanamide in the procedure of Example 1, the product is N-morpholinomethyl-2-(4-chloro-2-pyridyl)thiopropanamide.

EXAMPLE 12

A solution of 11.8 g. of 2-pyridylacetonitrile in 30 ml. of dimethylsulfoxide is added to a suspension of 2.4 g. of sodium hydride in 50 ml. of dimethylsulfoxide with stirring. The mixture is heated on a steam bath for 2 hours, then cooled to room temperature. 2-Methyl-2-pentenyl-1-chloride (11.8 g.) is added dropwise with stirring. The mixture is heated on the steam bath, with stirring, for 10 hours, then most of the solvent is removed in vacuo. Water is added to the residue, then 200 ml. of ether is added. The ethereal solution is separated from the aqueous layer and rinsed several times with water, then dried, concentrated and distilled to give 4-methyl-2-(2-pyridyl)-4-heptenenitrile.

Treating the above prepared nitrile with hydrogen sulfide by the procedure described in Example 9 gives 4-methyl-2-(2-pyridyl)-4-thioheptenamide.

Using 4-methyl-2-(2-pyridyl)-4-thioheptenamide in place of 3-methyl-2-(2-pyridyl)thiobutanamide in the procedure of Example 1 gives 4-methyl-N-morpholinomethyl-2-(2-pyridyl)-4-thioheptenamide.

EXAMPLE 13

By the procedures described in Example 9, α-(6-methyl-2-pyridyl)-2-propenol is treated with thionyl chloride, the resulting 2-(1-chloro-2-propenyl)-6-methylpyridine is reacted with sodium cyanide and the 2-(6-methyl-2-pyridyl)-3-butenenitrile is treated with hydrogen sulfide to give 2-(6-methyl-2-pyridyl)-3-thiobutenamide.

Reacting 2-(6-methyl-2-pyridyl)-3-thiobutenamide with morpholine and formalin by the procedure of Example 1 gives N-morpholinomethyl-2-(6-methyl-2-pyridyl)-3-thiobutenamide.

EXAMPLE 14

A solution of 1.66 g. (0.01 mole) of 2-(2-pyridyl)-thiopropanamide in 20 ml. of methanol is treated with 1.1 g. (0.015 mole) of morpholine and then with 0.45 g. (0.015 mole) of formaldehyde. The mixture is kept for 48 hours at 25°C., then concentrated in vacuo at 25°C. The residue is dissolved in a minimum of ethanol and treated with a 5% solution of oxalic acid in ethanol. Ether is added and the precipitate is filtered off and recrystallized from ethanol to give N-morpholinomethyl-2-(2-pyridyl)thiopropanamide oxalate.

The oxalate salt is suspended in water and basified with 5% aqueous sodium carbonate solution, then extracted with chloroform. The solvent is evaporated from the extracts and the residue is triturated with hexane. The solid is recrystallized from ether to give N-morpholinomethyl-2-(2-pyridyl)thiopropanamide, m.p. 69°-71°C.

EXAMPLE 15

A solution of 1.0 g. (0.005 mole) of 3-methyl-2-(2-pyridyl)thiobutanamide in 20 ml. of methanol is treated with 0.65 g. (0.0075 mole) of piperidine and then with 0.23 g. of formaldehyde. The mixture is kept for 72 hours at 25°C., then concentrated in vacuo at 25°C. The residue is suspended in water and then extracted into chloroform. The chloroform is evaporated from the extracts and the residue is dissolved in hexane and cooled to -60°C. on a dry ice bath. Upon warming to 25°C., the hexane solution was decanted from insoluble oil and then evaporated in vacuo. The residue is vacuum dried at 0.005 mm. and 25°C. to give 3-methyl-N-piperidinomethyl-2-(2-pyridyl)thiobutanamide.

EXAMPLE 16

A solution of 1.0 g. (0.005 mole) of 3-methyl-2-(2-pyridyl)thiobutanamide in 20 cc. of methanol is treated with 0.54 g. (0.0075 mole) of pyrrolidine and then with 0.23 g. (0.0075 mole) of formaldehyde. The mixture is kept at 25°C. for 72 hours, then worked up as in Example 15 to give, after vacuum drying at 0.005 mm. and 25°C., 3-methyl-N-pyrrolidinomethyl-2-(2-pyridyl)thiobutanamide.

EXAMPLE 17

A solution of 1.94 g. (0.01 mole) of 3-methyl-2-(2-pyridyl)thiobutanamide in 40 ml. of methanol is treated with 1.1 g. (0.015 mole) of diethylamine and 0.45 g. of formaldehyde. The mixture is kept for 48 hours at 25°C., then at 0°C. for 48 hours. The solvent is evaporated and the residue is dissolved in chloroform and washed with water. The solution is dried and the solvent is evaporated off. The residue is vacuum dried at 0.005 mm. and 25°C. for 6 hours to give N-diethylaminomethyl-3-methyl-2-(2-pyridyl)-thiobutanamide.

EXAMPLE 18

By the procedure of Example 17, using in place of diethylamine, the following di-lower alkylamines:

dimethylamine

dipropylamine

dibutylamine

the products are, respectively:

N-dimethylaminomethyl-3-methyl-2-(2-pyridyl)thiobutanamide

N-dipropylaminomethyl-3-methyl-2-(2-pyridyl)thiobutanamide

N-dibutylaminomethyl-3-methyl-2-(2-pyridyl)thiobutanamide.

EXAMPLE 19

By the procedure of Example 15, using in place of 3-methyl-2-(2-pyridyl)thiobutanamide the following thioamides:

2-(2-pyridyl)thiopropanamide

2-(2-pyrazinyl)thiobutanamide

2-(2-pyridyl)-4-thiopentenamide

the products are, respectively:

N-pyrrolidinomethyl-2-(2-pyridyl)thiopropanamide

N-pyrrolidinomethyl-2-(2-pyrazinyl)thiobutanamide

N-pyrrolidinomethyl-2-(2-pyridyl)-4-thiopentenamide.

EXAMPLE 20

By the procedure of Example 5, using pyrrolidine in place of morpholine, the product is N-pyrrolidinomethyl-2-(2-pyridyl)thioacetamide.

Similarly, using the following amines:

piperidine

diethylamine

1-methylpiperazine

the products are, respectively:

N-piperidinomethyl-2-(2-pyridyl)thioacetamide

N-diethylaminomethyl-2-(2-pyridyl)thioacetamide

N-(4-methylpiperazinomethyl)-2-(2-pyridyl)thioacetamide.

EXAMPLE 21

By the procedure of Example 5, using pyrrolidine in place of morpholine and the following thioamides in place of 2-(2-pyridyl)thioacetamide:

2-(2-pyrazinyl)thioacetamide

2-(2-quinolyl)thioacetamide

2-(2-pyrrolyl)thioacetamide

2-(4,6-dimethyl-2-pyrimidyl)thioacetamide

2-(4-thiazolyl)thiopropanamide

the products are, respectively:

N-pyrrolidinomethyl-2-(2-pyrazinyl)thioacetamide

N-pyrrolidinomethyl-2-(2-quinolyl)thioacetamide

N-pyrrolidinomethyl-2-(2-pyrrolyl)thioacetamide

N-pyrrolidinomethyl-2-(4,6-dimethyl-2-pyrimidyl)-thioacetamide

N-pyrrolidinomethyl-2-(4-thiazolyl)thiopropanamide.

EXAMPLE 22

By the procedure of Example 14, 2-benzyl-2-(2-pyridyl)thioacetamide is reacted with morpholine and formaldehyde to give 2-benzyl-N-morpholinomethyl-2-(2-pyridyl)-thioacetamide.

By the same procedure, using diethylamine in place of morpholine, the product is 2-benzyl-N-diethylaminomethyl-2-(2-pyridyl)-thioacetamide.

Similarly, using pyrrolidine in place of morpholine, the product is 2-benzyl-N-pyrrolidinomethyl-2-(2-pyridyl)-thioacetamide.

EXAMPLE 23

3-Methyl-N-morpholinomethyl-2-(2-pyridyl)thiobutanamide (500 mg.) in ethanol is treated with ethereal hydrogen chloride to give, after filtering, 3-methyl-N-morpholinomethyl-2-(2-pyridyl)thiobutanamide hydrochloride.

By the same procedure, using ethereal hydrogen bromide, the hydrobromide salt is prepared.

EXAMPLE 24

3-Methyl-N-pyrrolidinomethyl-2-(2-pyridyl)thiobutanamide is treated with an equimolar amount of maleic acid in ethanol to give 3-methyl-N-pyrrolidinomethyl-2-(2-pyridyl)thiobutanamide maleate.

EXAMPLE 25

A solution of 1.94 g. (0.01 mole) of 3-methyl-2-(2-pyridyl)thiobutanamide in 40 ml. of methanol is treated with 1.6 g. (0.015 mole) of N-methylaniline and 1.22 ml. of 37% formalin solution. The reaction is kept at 25°C. for 12 hours, then refluxed for 4 hours. The solvents are evaporated in vacuo and the residue is triturated with ethyl acetate and cooled, then filtered. The filtrate is evaporated in vacuo and the resulting oil is triturated with cold ether to give 3-methyl-N-(N-methyl-N-phenylaminomethyl)-2-(2-pyridyl)thiobutanamide, which after recrystallization from ether melts at 95°-97°C.

By the same procedure using N-ethylaniline in place of N-methylaniline, the product is 3-methyl-N-(N-ethyl-N-phenylaminomethyl)-2-(2-pyridyl)thiobutanamide.

Similarly, using the appropriate N-lower alkylanilines, 3-methyl-N-(N-propyl-N-phenylaminomethyl)-2-(2-pyridyl)thiobutanamide and 3-methyl-N-(N-butyl-N-phenylaminomethyl)-2-(2-pyridyl)thiobutanamide are prepared.

EXAMPLE 26

    Ingredients              Amounts                                               ______________________________________                                         3-Methyl-N-morpholinomethyl-                                                    2-(2-pyridyl)thiobutanamide                                                                            100 mg.                                               Lactose                   75 mg.                                               Magnesium stearate        5 mg.                                                ______________________________________                                    

The ingredients are mixed and filled into a hard gelatin capsule.

EXAMPLE 27

    Ingredients               Amounts                                              ______________________________________                                         N-morpholinomethyl-2-(2-pyridyl)-                                               thiopropanamide          75 mg.                                               Calcium sulfate dihydrate 100 mg.                                              Sucrose                   25 mg.                                               Starch                    15 mg.                                               Talc                      5 mg.                                                Stearic acid              3 mg.                                                ______________________________________                                    

The sucrose, calcium sulfate dihydrate and N-morpholino-2-(2-pyridyl)thiopropanamide are thoroughly mixed and granulated with 10% gelatin solution. The wet granules are screened, dried and then mixed with the starch, talc and stearic acid, screened and compressed into a tablet.

The compositions prepared as in Examples 26 and 27 are administered orally to a subject having excessive gastric acid secretion within the dose ranges given hereabove. 

What is claimed is:
 1. A pharmaceutical composition having gastric acid secretion inhibitory activity, in dosage unit form, comprising a pharmaceutical carrier and a gastric acid secretion inhibiting amount of a thioacetamide compound of the formula: ##EQU3## in which: R₁ is 2-pyridyl; [R₂ is hydrogen, lower alkyl, lower alkenyl or --(CH₂)_(n) -phenyl; R₃ is di-lower alkylamino, N-lower alkyl-N-phenylamino, pyrrolidino, piperidino or morpholino and n is 0 or 1 or a pharmaceutically acceptable acid addition salt thereof.
 2. The pharmaceutical composition of claim 1 in which R₂ is lower alkyl and R₃ is morpholino.
 3. The pharmaceutical composition of claim 1 in which the thioacetamide compound is 3-methyl-N-morpholinomethyl-2-(2-pyridyl)thiobutanamide.
 4. The pharmaceutical composition of claim 1 in which the thioacetamide compound is N-morpholinomethyl-2-(2-pyridyl)thiopropanamide.
 5. The pharmaceutical composition of claim 1 in which the thioacetamide compound is 3-methyl-N-pyrrolidinomethyl-2-(2-pyridyl)thiobutanamide.
 6. The pharmaceutical composition of claim 1 in which the thioacetamide compound is N-diethylaminomethyl-3-methyl-2-(2-pyridyl)thiobutanamide.
 7. A method of inhibiting gastric acid secretion in a subject having excessive gastric acid secretion which comprises administering to said subject an effective gastric acid inhibiting amount of a thioacetamide compound of the formula: ##EQU4## in which: R₁ is 2-pyridyl;R₂ is hydrogen, lower alkyl, lower alkenyl or --(CH₂)_(n) -phenyl; R₃ is di-lower alkylamino, N-lower alkyl-N-phenylamino, pyrrolidino, piperidino or morpholino and n is 0 or 1or a pharmaceutically acceptable acid addition salt thereof.
 8. The method of claim 7 in which R₂ is lower alkyl and R₃ is morpholino.
 9. The method of claim 7 in which the thioacetamide compound is 3-methyl-N-morpholinomethyl-2-(2-pyridyl)thiobutanamide.
 10. The method of claim 7 in which the thioacetamide compound is N-morpholino-2-(2-pyridyl)thiopropanamide. 